The Composition and Properties of Purified Rapeseed Lecithins

The chemical and physical parameters of various quality grade rapeseed lecithins obtained from raw lecithin and from lecithin wet gum were evaluated. The chemical composition, fatty acids and metals contents, acid, peroxide and iodine values were determined. From the data it could be suggested, that the purified rapeseed lecithins obtained from 00-varieties, especially prepared directly from rapeseed wet gum are the interesting and valuable material for use in pharmacy, food industry and cosmetics.     

Emulsifying Properties of Lecithin Containing Different Fatty Acids Obtained by Immobilized Lecitase Ultra-Catalyzed Reaction

Lecitase Ultra and 6 triacylglycerol lipases (lipases PS, M, AH, AY, R, and AK) were immobilized on Amberlite XAD 7HP and used to catalyze the acidolysis reaction between lecithin and capric acid (C10:0) for comparison. The highest molar incorporation value (51.0 mol%) was observed for the immobilized Lecitase Ultra. Further, immobilized Lecitase Ultra was selected for catalyzing acidolysis between lecithin and fatty acids with different chain lengths (C6:0, C8:0, C10:0, C12:0, and C14:0). After reaction, free fatty acids were removed by SPE and the resultant was called modified lecithin fraction 1 (MLF1). The highest molar incorporation value was obtained for C10:0 (51.0 mol%) at 45 °C with a mole ratio of 10/1 (C10:0/lecithin) for 72 h. After removal of lysophosphatidylcholine by solid-phase extraction from MLF1, the resultant modified lecithin fraction 2 (MLF2) was used to prepare an oil-in-water emulsion. All emulsions prepared with MLF2 exhibited significantly higher emulsion stability (ES) values (16.2–17.7) and smaller particle sizes (d ₃₂ 0.40–0.49 μm, d ₄₃ 0.75–1.01 μm) than the emulsion prepared with unmodified lecithin (ES 14.1, d ₃₂ 0.76 μm, d ₄₃, 1.26 μm) (P < 0.05). Furthermore, less clarification and droplet aggregation were observed in emulsions prepared with MLF2 than in lecithin-based emulsions. Overall, the MLF2s showed better emulsifying properties than lecithin.     

有机硅表面活性剂的制备及乳化性能

以烯丙基聚氧乙烯醚、低含氢硅油为原料,氯铂酸的异丙醇溶液为催化剂,在无溶剂条件下合成出有机硅表面活性剂,并用红外光谱对其结构进行表征。正交实验表明,较佳的合成条件为:原料中SiH与C=C的量之比为1∶1.1,催化剂用量为10μg/g(以铂含量计),反应温度100℃,反应时间6 h,聚醚转化率达88.58%;在此条件下制得的有机硅表面活性剂的最低表面张力为27.8 mN/m、浊点为60℃、临界胶束质量浓度为0.32 g/L。将其与Span 60复配后用于乳化二甲基硅油,可制得稳定的硅油乳液。激光粒度仪测得乳液平均粒径为17.556μm,与一般Span/Tween复配乳化剂乳化的硅油乳液相比,乳液粒径更小,乳液更稳定。     

Rheological Properties of Sunflower Margarine

The consistency of margarine is affected by a number of different factors. The governing factors are particularly the formulation of the margarine fat and technology parameters of the processing. The effect of the margarine fat formulation on rheological properties of margarine made under constant conditions on a laboratory equipment was studied. In soft margarines to be used directly as spreads, their spreadability even at lower temperatures during the storage in refrigerator is of importance, which means that their rheological parameters (static and dynamic yield value, apparent viscosity) should be independent of temperature as little as possible in a temperature interval of 5 to 25°C. The experiments performed indicated that under the constant conditions of a laboratory preparation used, optimum rheological properties were achieved with samples prepared from a margarine fat with a composition of the 50–65% soft sunflower oil and 35–50% hardened sunflower oil 36°C.     

Germicidal Properties of Ozonated Sunflower Oil

The aim of this work was to establish the minimal inhibition concentration (MIC) of ozonated sunflower oil for various microorganisms. To determine the influence of the ozonated medium on the growth of bacteria Bacillus subtilis, Escherichia coli and yeast Candida albicans the Petri dish method was used. Chemical and physical properties of ozonated sunflower oil were additionally studied. Microbiological studies proved that these microbes have various sensibility against ozonated oil. The most resistant are gram-negative bacteria E. coli and the yeast C. albicans. Gram-positive bacteria, B. subtilis turned out to be less resistant, because no growth was observed for preparation with an ozone dose of 200 mgO₃/g oil.     

填充聚丙烯复合材料不同温度下弯曲性能研究

分别对PP、PP-TD10、PP-TD20、PP-TD30、PP-TD40体系进行不同温度(-40、-30、23、60、80、100、120℃)的弯曲性能研究.研究表明,随着温度的降低,聚丙烯复合材料的弯曲强度和弯曲模量不断增加,另外随着填充比例的增加复合材料的弯曲强度和弯曲模量也不断上升.以23℃为基准,PP-TD2...     

阳离子乳化沥青CA砂浆的制备及性能

CA砂浆是板式无碴轨道结构弹性调整层的核心。通过正交试验研究了水泥、沥青乳液和砂的用量对CA砂浆工作性能的影响规律。结果表明:流动度随着水泥、沥青和外加水用量的增加而增加,而随着砂的用量的增加而减小;膨胀率随着铝粉掺量的增加而增大;弹性模量随着水泥和砂的用量的增加而增加,随着沥青乳液用量的增加而降低。     

双子咪唑啉季铵盐的合成及其乳化性能

首先,以二丁胺和环氧氯丙烷为原料合成N-丁基-N,N-二(3-氯-2-羟丙基)丁烷-1-铵盐;然后,利用其与长链烷基咪唑啉进行季铵化反应合成双子咪唑啉季铵盐,并通过FTIR和1HNMR验证了目标产物的结构;最后,利用合成的双子咪唑啉季铵盐和秦皇岛AH-70重交道路沥青制备乳化沥青,进行双子咪唑啉季铵盐乳化性能的考察。结果表明,在皂液p H=5.0、沥青温度为135℃、皂液温度为55℃、乳化剂加量为1.5%(占乳化沥青总质量的百分数)的条件下制备的乳化沥青达到交通部JTG F40-2004的质量要求。     

淀粉辛酸酯的制备及其乳化性能的研究

将淀粉与辛酰氯在有机溶剂中反应制备了不同取代度的淀粉辛酸酯,采用红外光谱(FTIR)对其结构进行了表征。此外,进一步研究了淀粉辛酸酯在大豆油与水乳液体系中取代度、淀粉辛酸酯的质量分数和油水体积比等条件对淀粉辛酸酯乳液乳化性及乳化稳定性的影响。结果表明,在取代度为0.37、淀粉辛酸酯质量分数为7%时,淀粉辛酸酯显示出较好的乳化性能。在大豆油/水乳液体系中,当油水体积比为4∶6时,乳液的乳化性较好。而在油水体积比为2∶8时,乳液的乳化稳定性较好。     

改性葵花秸秆对铅离子的吸附性能研究

为了研究改性葵花秸秆对铅离子的吸附性能,采用氢氧化钠处理、高锰酸钾和浓硫酸氧化的方法对葵花秸秆粉末改性,由单因素实验来考察pH、吸附剂用量、温度、时间对铅离子去除率的影响;再设计正交实验,确定最优吸附条件;最后进行吸附动力学模型分析.结果表明:pH=6、吸附剂用量1.0 g、温度25℃、时间60 min时吸附效果最好,...     

不同矿物掺合料对改性硫氧镁水泥性能影响的研究

为探究矿物掺合料对改性硫氧镁水泥的影响及作用机理,分别将不同掺量的粉煤灰、矿粉掺入改性硫氧镁水泥中,对其力学性能、耐水性和耐酸性进行测试,并结合X射线衍射和扫描电镜对其物相组成及微观形貌进行表征和分析。研究结果表明:粉煤灰的掺入会提高改性硫氧镁水泥的3 d强度,但后期强度有所下降,当粉煤灰掺量大于20%(质量分数)时,其28 d抗压强度相较于基准组损失了14.7%;掺入矿粉对改性硫氧镁水泥的前期强度影响较小,并导致后期强度下降,当矿粉掺量为30%~40%(质量分数)时,水泥的28 d强度损失率高达17.3%。适量的粉煤灰与矿粉均能够提升改性硫氧镁水泥的耐水性和耐硫酸腐蚀性,其中水泥的耐硫酸腐蚀性随着粉煤灰掺量的增加而增强,耐硫酸腐蚀效果最好时矿粉掺量为20%。     

不同己烯含量对PBH性能及其改性聚丙烯性能影响的研究

采用本实验室自制的负载钛催化剂[TiC l4/MgC l2-A l(i-Bu)3]体系,合成了不同己烯初始摩尔含量1-丁烯-1-己烯共聚物(PBH)热塑性弹性体,研究其结构与性能的关系;并用不同己烯初始摩尔含量的PBH对聚丙烯(PP)进行共混改性,研究了共混物的力学性能和热性能。结果表明,随着共聚物中己烯初始摩尔含量的增加,共聚物的拉伸强度、撕裂强度和硬度均下降;而断裂伸长率明显增大。当共混物中PBH含量一定(10%)时,随着共聚物中己烯初始摩尔含量的增加,共混物的冲击强度和断裂伸长率均明显增大,而拉伸强度、硬度和耐热温度有一定的下降。     

不同膨胀体积改性膨胀石墨及其填充PA66性能

采用化学氧化法制备了不同膨胀体积的膨胀石墨(EG),通过聚丙烯酸酯对不同膨胀体积的EG进行包覆改性,利用改性后的EG制备改性EG/聚酰胺66(PA66)复合材料,研究了不同膨胀体积的改性EG对复合材料力学性能和导热性能的影响。结果表明,EG经丙烯酸酯改性后,EG的表面粗糙度和活性基团明显增加;复合材料弹性模量和弯曲强度均随改性EG膨胀体积的增加而增加,与未膨胀石墨相比,分别提升了36.1%、25.8%;拉伸强度、断裂伸长率和热导率随膨胀体积的增加呈先增加后减小的趋势。拉伸强度在EG膨胀体积为40 mL/g时达到最大值,为75.6 MPa;热导率在膨胀体积为20 mL/g时最佳,为2.56 W/(m·k),与未膨胀石墨相比,拉伸强度和热导率分别提升了33.3%和30.1%。     

Lecithins and lysolecithins of wheat flour

Lecithin and lysolecithin from the bound lipid of Thatcher wheat endosperm were separated and purified by column and thin-layer silicic acid chromatography. Lecithin was hydrolyzed with phospholipaseA (Crotalus adamanteus) and the products isolated and purified by silicic acid chromatography. The fatty acid composition of the original lecithin and lysolecithin and of the hydrolysis products was determined by gas-liquid chromatography. The fatty acids in the beta position of the lecithin were found to be almost entirely unsaturated, whereas those in the alpha position were saturated and unsaturated in nearly equal amounts. The differences between the fatty acid composition of the original lysolecithin and that of the lysolecithin obtained by hydrolysis of lecithin with phospholipaseA suggested the presence of both alpha and beta acyl species in the naturally occurring lysolecithin. Contribution No. 48, Food Research Institute, Research Branch, Canada Department of Agriculture, Ottawa, Canada.     

乳化条件对自乳化聚乙烯蜡乳液性能的影响

通过对马来酸酐接枝聚乙烯蜡（PEW-g-MAH）接枝共聚物进行皂化改性制备自乳化聚乙烯蜡,探讨了固含量和乳化条件对自乳化聚乙烯蜡的自乳化性及聚乙烯蜡乳液外观、分散性、稳定性、粒径及其分布的影响。结果表明,固含量是影响自乳化聚乙烯蜡乳化性的主要因素,只有当聚乙烯蜡乳液的固含量大于30 %时,自乳化聚乙烯蜡自乳化后方能得到分散良好、长期稳定且粒径分布均一的聚乙烯蜡乳液;乳化温度、乳化时间及剪切速率等乳化条件对乳液的性能均有影响,但乳化温度对自乳化聚乙烯蜡乳液的性能影响较大,乳化温度过高或者过低均对乳液分散和稳定不利,最佳的乳化温度为130 ℃。     

不同S/B比例的SBS改性沥青的分散形态及性能

以两种组成比例不同的SBS(791、792)为例,研究了S／B质量比对改性沥青分散形态与性能的影响。结果表明：S／B不同的SBS由于与沥青的相容性不同,对改性沥青的分散形态与性能有所不同。同等质量分数下,S／B高的SBS改性沥青的针入度较小。小用量范围内S／B低的改性沥青软化点高;用量超过5％后,S／B高的改性沥青软化点则较高。S／B低的改性沥青的5℃延度较好,弹性恢复率也较优。当SBS含量为5％时,S／B低的改性沥青的稳定性更好。     

不同添加方式对改性丙烯酸胶性能的影响

制备一种改性丙烯酸胶,并提高其韧性、耐冲击性能,采用不同的添加方式,第一种添加方式：A组分中加ABS树脂和氯丁橡胶,B组分加ABS树脂;第二种添加方式：A组分中加ABS树脂和氯丁橡胶,B组分加ABS树脂和氯丁橡胶;第三种添加方式,在A组分中只加橡胶,B组分只加ABS树脂。考察了ABS树脂的添加量对改性丙烯酸胶性能的影响。结果表明,当采用第二种添加方式,且ABS树脂添加量为17%时,其黏度合适,且其拉伸剪切强度和耐冲击强度较高,热贮存稳定极佳。     

Pharmacokinetic Properties of Fibre Materials Modified by Co-Immobilization of Different Biologically Active Substances

The possibility of manufacturing dressings with a combined biological action by modifying fibre materials of different types with combined immobilization of an enzyme — protease C — and a polymeric antimicrobial — polyhexamethyleneguanidine hydrochloride or polyethyleneimine with glutaraldehyde — was demonstrated. It was shown that with respect to the maximum stability of the enzyme, the fibre materials used for immobilization of protease C together with PEI or PHMG are in the order: PCA > CG > CG—PE. It was found that fibre materials containing immobilized protease C and polyhexamethyleneguanidine hydrochloride or polyethyleneimine exhibit a higher level of activity than the native enzyme at pH 6-9 corresponding to the conditions of use.     

不同乳化方法对30％毒死蜱·噻嗪酮水乳剂稳定性的影响

[目的]为研究不同乳化方法对农药水乳剂物理稳定性的影响,通过稳定性分析仪扫描和粒径测试研究了4种乳化方法制备30％毒死蜱·噻嗪酮水乳剂的稳定性.[结果]溶剂用量12％时,乳化剂加入油相时水乳剂粒径较小;扫描后1″和3″轻微沉降、2″和4″沉降明显,稳定性指数表明1″最稳定.溶剂用量27％时,1″粒径最小;扫描后1″变化不显著、2″沉降明显,1″径变化较小且最稳定.样品存放后外观与短期扫描结果一致.[结论]制备工艺对水乳剂稳定性影响显著,当溶剂用量27％时,采取将乳化剂加入油相中混匀后再逐渐加人水相中剪切为制备该制剂的最佳工艺.     

Mapping the Chemical Variability of Vegetable Lecithins

There is an increasing interest in vegetable lecithins because of their broad usage in many food and cosmetic applications. In this research, the chemical variability of commercial lecithins from soy, sunflower and rapeseed were mapped. The acetone insoluble matter, total phospholipid content and their compositions were determined. Significant correlation coefficients were observed between phosphatidylcholine and phosphatidic acid (?0.84), phosphatidylethanolamine and phosphatidylinositol (?0.86), monounsaturated fatty acid and polyunsaturated fatty acid (?0.97). Principal component analysis was used to group the lecithins according to their sources. Rapeseed lecithin was found to be the most different product compared to soy and sunflower lecithin.